Spray gun reservoir with oversize, fast-fill opening

ABSTRACT

A spray gun reservoir has an oversize central opening  130  at one end allowing liquid to be added to the reservoir for fast filling with reduced risk of spillage. A cap member  132  is connectable to the reservoir and has a spout  115  providing a fluid outlet of reduced size relative to the opening  130  for connection to the spray gun. The reservoir can be disconnected from the cap member  132  when it is desired to add liquid to the reservoir. In this way, the reservoir can be re-filled in use.

FIELD OF THE INVENTION

This invention concerns improvements in or relating to liquid supplyassemblies for use with spraying apparatus such as a spray gun. Moreespecially, the invention relates to liquid supply assemblies in which areservoir containing the liquid to be sprayed is mounted on the spraygun.

BACKGROUND OF THE INVENTION

Spray guns are widely used to apply a liquid to a substrate in a varietyof industries. In the known spray guns, the liquid is contained in areservoir attached to the gun from where it is fed to a spray nozzle. Onemerging from the spray nozzle, the liquid is atomised and forms a spraywith compressed air supplied to the nozzle. The liquid may be gravityfed or suction fed or, more recently, pressure fed by an air bleed fromthe compressed air line to the reservoir or even from the spray gunitself.

A common application of spray guns is in vehicle body repair shops whenre-spraying a vehicle that has been repaired following an accident. Atypical paint finish may require application of a primer, base coat, topcoat and a clear lacquer. Traditionally, the reservoir is a rigid potdetachably mounted on the spray gun by engagement of complementary screwthreads on the spray gun and pot. The spray gun and pot have to bethoroughly cleaned when changing the liquid to be sprayed to avoidcross-contamination which may adversely affect the finish. This isespecially important when spraying part of a vehicle to match exactlythe colour of the existing colour of the adjacent bodywork. Cleaning thespray gun and pot is time consuming and often requires the use ofsolvents which are costly and may present a health hazard to theoperator.

We have previously proposed in WO 98/32539 a reservoir in which theliquid is contained in a disposable lid/liner assembly. The liner is inthe form of an open-topped container that is a close fit inside an outerrigid pot, and the lid is secured over the open end of the liner by acollar screwed onto the pot. The reservoir is releasably connected tothe spray gun by means of a spout integral with the lid and throughwhich liquid is withdrawn from the reservoir in use.

In this way, after spraying, the reservoir can be detached from thespray gun, the collar released and the lid/liner assembly removed fromthe outer pot and thrown away. The outer pot and collar can then bere-used with a new, clean liner and lid for supplying a different liquidto the spray gun. As a result, the amount of cleaning required isconsiderably reduced and the spray gun can be readily adapted to applydifferent liquids in a simple manner.

For some applications of the spray gun, a larger volume of liquid thanthe reservoir can hold may be required. For example, when painting alarge area or applying several coats of the same liquid to the same ordifferent vehicles such as when using a primer or lacquer finish. Inthis case, the reservoir can be detached from the gun, the collarreleased and the lid removed to allow liquid to be added to the liner.The reservoir is then re-assembled and re-attached to the spray gun.

Dis-assembly and re-assembly of the reservoir is time consuming and canresult in spillage of liquid especially when the lid is removed from theliner. Also, removing the lid to add more liquid to the liner increasesthe risk of contamination from other sources, e.g. dust or dirt.

The alternative of adding liquid to the reservoir through the spout inthe lid so as to avoid dis-assembly is slow due to the spout being ofsmall size compatible with the connection to the spray gun so thatliquid cannot be freely poured into the reservoir through the spout.Also the spout may contain a filter or a filter may be positioned in thelid across the inner end of the spout to remove any unwanted solidparticles contained in the liquid withdrawn from the reservoir in use.Access to the filter requires dis-assembly of the reservoir and thepresence of such filter further slows the addition of liquid to thereservoir through the spout.

Furthermore, if the liquid contains solid particles these will betrapped on the wrong side of the filter. As a result, when the reservoiris re-attached to the spray gun, the particles may be picked up withliquid withdrawn from the reservoir and pass to the spray gun. This maylead to a blockage within the spray gun. Alternatively or additionally,the particles may be applied with the liquid to the surface beingsprayed with the result that the surface may have to be re-sprayed.

SUMMARY OF THE INVENTION

The present invention is intended to improve further our existing systemand provide additional benefits and advantages for the user.

More specifically, at least one embodiment of the present inventionprovides a liquid supply assembly for use with a spray gun that allowsliquid to be added in a simple manner.

Furthermore, at least one embodiment of the present invention provides aliquid supply assembly for use with a spray gun that can be suppliedempty or pre-filled with liquid.

Moreover, at least one embodiment of the present invention provides aliquid supply assembly for use with a spray gun that can be thrown awayafter use to reduce the amount of cleaning required.

Other benefits and advantages of the invention are referred to laterherein.

According to the present invention there is provided a liquid supplyassembly for use with spraying apparatus such as a spray gun as definedin claim 1.

As used herein, the term “liquid” refers to all forms of flowablematerials that can be applied to a surface using a spray gun (whether ornot they are intended to colour the surface) including (withoutlimitation) paints, primers, base coats, lacquers, varnishes and similarpaint-like materials as well as other materials such as adhesives,sealers, fillers, putties, powder coatings, blasting powders, abrasiveslurries, mould release agents and foundry. dressings which may beapplied in atomised or non-atomised form depending on the propertiesand/or the intended application of the material and the term “liquid” isto be construed accordingly.

By this invention, the fluid outlet of the reservoir is provided by thespout of the separate cap member releasably secured to the reservoir. Asa result, the opening in the reservoir can be oversize relative to thefluid outlet and the reservoir can be detached from the cap member toadd liquid to the reservoir through the opening without dis-assembly ofthe reservoir. In this way, liquid can be added to the reservoir in asimple manner so that the risk of spillage and/or contamination of theliquid may be reduced.

This is of particular benefit if the capacity of the reservoir is lessthan the volume of liquid required for a particular application. Forexample, when spraying a large area, the user can detach the reservoirfrom the cap member to top-up the reservoir with additional liquid andre-attach the reservoir to the cap member.

It is also of benefit if it is desired to dilute the liquid beingsprayed. For example, when applying a finishing clearcoat such aslacquer, the user can detach the reservoir from the cap member to addsolvent to the reservoir to reduce the viscosity of the clearcoat for‘fading-out or blending’ and re-attach the reservoir to the cap member.

The reservoir may be collapsible as liquid is withdrawn. For example,the side wall may be flexible in comparison to the end wall so as to becapable of deforming to collapse the reservoir in an axial directionfrom the second end towards the first end. Preferably, the end wall iscomparatively rigid relative to the side wall to provide stability andallow the reservoir to be gripped by the user without collapsing whenattaching the reservoir to and detaching the reservoir from the capmember. In a preferred arrangement, the reservoir is provided with acomparatively rigid base at the second end such that the reservoir canbe inverted and stood on the base for adding liquid through the openingin the end wall.

The reservoir may be formed in one piece. For example, the reservoir maybe a moulding such as a blow moulding. Alternatively, the base and sidewall may be formed in one piece with the end wall being formed as aseparate piece that is secured to the side wall. For example, the baseand side wall may form an open topped container and the end wall mayform a lid for the container. The lid may be permanently secured to thecontainer. For example, the lid may be welded or adhesively bonded tothe container. Alternatively, the lid may be releasably secured to thecontainer. For example, the lid may be clamped to the container.

The cap member may be a screw-fit on the reservoir. Alternatively, thecap member may be releasably secured to the reservoir by any othersuitable means, for example a snap-fit. In a preferred arrangement, thecap member comprises a base defining a socket with an internal screwthread to receive an externally threaded spigot bounding the opening inthe reservoir and the spout extends from the base of the socket awayfrom the reservoir.

The spout is of reduced size relative to the opening in the end wall ofthe reservoir for connection to the spray gun inlet. For example, thespout may have a diameter less than half the diameter of opening in theend wall of the reservoir, more preferably less than a third thediameter of the opening and more preferably less than a quarter thediameter of the opening. In one embodiment, the opening has a diameterof 50-60 mm, preferably 53 mm (about 2″) and the spout has a diameter of10-15 mm (about ½″).

Preferably, the opening is located centrally in the end wall. In thisway, the size of the opening can be maximised for rapid filling of thereservoir. Advantageously, the spout in the cap member is coaxial withthe opening so that, when connected to the spray gun, the reservoir isaligned with the central longitudinal axis of the spray gun. As aresult, balance, handling of the spray gun is not adversely affected bythe weight of the reservoir and the liquid therein. Advantageously, thecap member is adapted for releasable connection to the sprayingapparatus. For example, the cap member and spraying apparatus may beprovided with co-operating bayonet type formations. In this way, the capmember can be connected to and released from the spraying apparatus withor without the reservoir being attached by a simple action requiringminimum effort or manual dexterity by the user.

Preferably, the spray gun is provided with a socket to receive the spoutand the bayonet type formations are engageable to retain the spout inthe socket. The socket may be an integral part of the spray gun or itmay be a separate part secured to the spray gun. For example, the socketmay be formed by an inlet adaptor secured to the spray gun.

In one arrangement, the bayonet type formations are engageable withinthe socket. For example, the spout may be provided with opposed bayonetlugs at the free end that are received in bayonet grooves in the socket.In another arrangement, the bayonet type formations are engageableexternally of the socket. For example, the socket may have an externalflange co-operable with a pair of hook members extending from the baseof the cap member on opposite sides of the spout.

Preferably, the bayonet formations are engageable/disengageable withless than one complete turn of the cap member relative to the spray gunand the releasable connection between the cap member and the reservoiris arranged so that the reservoir is not disconnected from the capmember when connecting/disconnecting the cap member to/from the spraygun. For example, where the cap member is a screw fit on the reservoir,the screw threads may require more than one complete turn of thereservoir relative to the cap member to secure/release the reservoirto/from the cap member. Alternatively or additionally, the screw threadson the cap member and reservoir may be reversed so that the cap memberis released from the reservoir by unscrewing in the opposite directionto that used to connect the cap member to the spray gun.

The cap member may include a filter for removing any unwanted solidparticles contained in the liquid withdrawn from the reservoir. Forexample, the filter may be located in the spout. Alternatively, thefilter may be seated at the base of the socket to extend across theopening to the spout. In this way, liquid can be added to the reservoirthrough the opening without filtering to remove any solid particles.Furthermore, if the filter becomes blocked in use, the cap member can bereplaced.

Alternatively, liquid added to the reservoir may be filtered to removeany solid particulates so that filtering of the liquid withdrawn fromthe reservoir in use is not required. In this way, the filter in the capmay be omitted.

The reservoir may be supplied empty for the user to fill with liquid andattach the cap member to connect the reservoir to the spray gun. Wherethe reservoir is collapsible, it may be collapsed to a compact form forstorage and transportation.

Alternatively, the reservoir may be supplied pre-filled with liquid andthe opening sealed until it is desired to use the liquid. For example,the opening may be sealed using a removable closure or a rupturablemembrane that is broken when the cap member is attached to thereservoir. In another arrangement, the cap member may be adapted to sealthe opening until it is desired to use the liquid. For example, the capmember may be provided with a removable seal at the base of the socketto close the spout. Alternatively, a rupturable membrane may be providedacross the end of the spout that is broken when the spout is attached tothe spray gun.

Pre-filling may be employed for liquids that can be packaged and storeduntil required without degrading. Thus, pre-filling may be especiallyuseful for liquids that can be supplied ready to use (i.e. withoutrequiring modification to match the colour to an existing colour). Forexample, base coats in standard colours of a specified shade and/orprimers or lacquers that can be supplied in a non-activated form andactivated (if necessary) by suitable means such as by exposure to asource of light (ultraviolet) or electrical energy when required.Whichever arrangement is employed, the reservoir can be re-filled in useby detaching the reservoir from the cap member, adding liquid throughthe opening and re-attaching the reservoir to the cap member.

In a preferred arrangement, the cap member has a base and a spout, thecap member being releasably secured to the reservoir by engagement ofcomplementary screw threads on the base and on the end wall around theopening, and the spout extends from the base away from the reservoir toprovide a fluid outlet of reduced cross-section relative to the opening.

Preferably, the reservoir is collapsible as liquid is withdrawn in use.For example, the end wall may be comparatively rigid compared to theside wall. In this way, the end wall provides stability and allows thereservoir to be gripped without collapsing when attaching the reservoirto and detaching the reservoir from the cap member, and the side wall iscollapsible in an axial direction towards the end wall as liquid iswithdrawn from the reservoir in use.

In one arrangement, the cap member has a socket provided with aninternal screw thread engageable with an external screw thread on aspigot extending around the opening in the end wall. In anotherarrangement, the marginal edge of the opening has an internal screwthread engageable with an external screw thread on the cap member.

In another preferred arrangement, the opening is oversize relative tothe flow requirements when the reservoir is connected to the spray gunin use, and the fluid outlet provided by the spout is of reducedcross-section relative to the opening, wherein the opening permitsfast-filling of the reservoir when the cap member is detached from thereservoir for adding fluid to the reservoir through the opening.

By providing the reservoir with an oversize, fast-fill opening, theaddition of liquid to the reservoir is facilitated in a simple mannerthat reduces the risk of spillage.

The invention will now be described in more detail, by way of exampleonly, with reference to the accompanying drawings, wherein:

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a prior art spray gun;

FIG. 2 is an exploded isometric view of the component parts of the paintreservoir shown in FIG. 1;

FIG. 3 is a perspective view of the assembled paint reservoir shown inFIG. 2;

FIG. 4 is a longitudinal section through the paint reservoir shown inFIG. 3;

FIG. 5 shows separation of the component parts of the paint reservoir ofFIG. 3 after use.

FIG. 6 is a perspective view of an adapter for connecting the paintreservoir to the spray gun;

FIG. 7 is a longitudinal section through the adapter shown in FIG. 6;

FIG. 8 is an exploded isometric view similar to FIG. 2 showing thecomponent parts of a paint reservoir according to a first embodiment ofthe invention;

FIG. 9 is a perspective view similar to FIG. 3 showing the assembledpaint reservoir of FIG. 8;

FIG. 10 is a longitudinal section through the paint reservoir of FIG. 9;

FIG. 11 is a perspective view of a cap member for use with the reservoirof FIGS. 8 to 10;

FIG. 12 is a longitudinal section showing the cap member of FIG. 11attached to the reservoir of FIGS. 8 to 10;

FIG. 13 is a perspective view of a reservoir and cap member according toa second embodiment of the present invention;

FIG. 14 is a perspective view of alternative cap member for use with thereservoir of FIGS. 8 to 10 or FIG. 13;

FIG. 15 is a plan view of an alternative adaptor for use with the capmember of FIG. 14 to connect the reservoir to the spray gun

FIG. 16 is a longitudinal section similar to FIG. 12 showing analternative connection between the cap member and reservoir; and

FIG. 17 is a longitudinal section similar to FIG. 12 showing a furtheralternative connection between the cap member and reservoir.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 of the drawings illustrates a prior art paint spray gun 1 of thegravity-feed type disclosed in our co-pending patent applicationpublished under No: WO 98/32539 the contents of which are incorporatedherein by reference.

The gun 1 comprises a body 2, a handle 3 which extends downwards fromthe rear end of the body, and a spray nozzle 4 at the front end of thebody. The gun 1 is manually-operated by a trigger 5 which ispivotally-mounted on the sides of the gun.

A paint pot 6, which contains paint (or similar material) to bedischarged by the gun, is located on the top of the body 2 andcommunicates with an internal passageway (not visible) which extendsthrough the gun to the nozzle 4.

In use, the gun 1 is connected via a connector 7 at the lower end of thehandle 3 to a source of compressed air (not shown) so that, when theuser pulls on the trigger 5, compressed air is delivered through the gunto the nozzle 4. As a result, paint delivered under gravity from the pot6 to the nozzle 4 is atomised on leaving the nozzle 4 and forms a spraywith the compressed air emerging from the nozzle 4.

Referring now to FIGS. 2 to 4 of the drawings, the paint pot 6 includesan outer container 8, a disposable liner 9, a disposable lid 10 and acollar 11. The liner 9 corresponds in shape to (and is a close fit in)the interior of the container 8 and has a narrow rim 12 at the open endwhich sits on the top edge of the container 8.

The lid 10 has a dependent skirt 13 at the peripheral edge which is apush-fit in the open end of the liner 9 and a central aperture 14 fromwhich extends a spout 15 forming a fluid outlet. The spout 15 isprovided at its free end with outward extensions 16 forming one part ofa bayonet connection. The aperture 14 is covered at the inner end of thespout 15 by a filter mesh 17 which may be a push fit in the skirt 13 ormay be an integral part of the lid 10. Alternatively, the filter may bea push fit in the spout 15.

The lid 10 is held firmly in place on the container 8 by the annularcollar 11 which screws onto the container 8 on top of the lid 10. In theassembled condition, the liner 9 and lid 10 form a reservoir forcontaining the paint or other liquid to be delivered to the nozzle 4 viathe spout 15.

The paint pot 6 is attached to the spray gun 1 through use of an adapter18 shown separated from the paint pot 6 in FIGS. 6 and 7. The adapter 18is a tubular component which is formed internally at one end with asocket 19 having the other part of the bayonet connection for attachmentto the spout 15 of the lid 10. At the other end 20, the adapter 18 isshaped to match the standard attachment of the spray gun paint pot(typically a screw thread).

The container 8 of the paint pot 6 is formed from a plastic material,for example polyethylene or polypropylene, and may be translucent (asshown in FIG. 2) or opaque, and of any suitable size. For use with apaint spray gun, containers 8 having a capacity of 250, 500 or 800 mlcould typically be used, although other sizes could be used if required.

In this embodiment, the container 8 is of generally cylindrical shapeclosed at one end 8A. The other end is open and side wall 8B is formedwith an external screw thread 8C. Base 8A is flat so that the container8 can stand unsupported on a flat surface and is formed with a centralair hole 8D. Internally, the side wall 8B tapers inwardly slightly fromthe open end to the base 8A.

The liner 9 is preferably transparent and is thermo-formed from a singlepiece of plastics material, preferably polyethylene or polypropylene.The shape of the liner 9 is dictated by and matches the internal shapeof the container 8. The liner 9, like the inside of the container 8, isof generally cylindrical shape closed at one end 9A and side wall 9Btapers inwardly slightly from the mouth towards the closed end 9A.

The base or closed end 9A is comparatively rigid but the side walls 9Bare flexible and can be made to collapse. Nevertheless, the liner 9 iscapable of standing, unsupported, on the base 9A with side walls 9Bextended and upright as shown in FIGS. 2 to 4.

When the liner 9 collapses, the comparatively rigid base 9A retains itsform but moves towards the rim portion 12 as a consequence of thecollapse of the side walls 9B, as illustrated in FIG. 5. The side walls9B collapse in a similar fashion to a plastic bag without being ruptured(e.g. by splitting, tearing or cracking).

The lid 10 is also formed from a plastic material, for example,polyethylene or polypropylene, and may be formed by an injectionmoulding process. The lid 10 may be translucent or opaque and may becoloured. The collar 11 may be a moulded plastic component, or it may bea machined metal (for example, aluminium) component. The adapter 18 maybe a metal or plastic component and may, for example, be formed fromaluminium and anodised or plated.

To use the paint pot 6, the adapter 18 is attached at the end 20 to thespray gun and is left in position. Then, with the paint pot 6disassembled as shown in FIG. 2, the liner 9 is pushed inside thecontainer 8. Paint is then put into the liner 9 and, if necessary, mixedwith other tinters, hardeners and thinners (solvents). The lid 10 isthen pushed into place and the collar 11 is screwed down tightly to holdthe lid 10 in position.

The top portion of the liner 9 is then trapped between the skirt 13 ofthe lid 10 and the sidewall 8B of the container 8, and the rim 12 of theliner 9 is trapped between the top edge of the container 8 and thecollar 11 as shown in FIG. 4. The spray gun 1 is then inverted from itsnormal operating position illustrated in FIG. 1 so that the end of thespout 15 can be attached to the adapter 18 after which the spray gun 1can be returned to its normal operating position for use in the usualway.

As paint is removed from within the liner 9, the sides 9B of the liner 9collapse as a result of the decreased pressure within the liner 9. Thebase 9A of the liner 9, being more rigid, retains its shape so that theliner 9 tends to collapse in the longitudinal rather than the transversedirection thereby reducing the possibility of pockets of paint beingtrapped in the liner 9.

The user can choose to evacuate the air from within the liner 9 beforeoperating the spray gun 1 although that is not essential. It does,however, increase the range of angles at which the spray gun 1 willfunction satisfactorily since there is no risk of air entering the spraygun 1 from the paint pot 6. To evacuate the air from within the liner 9,the trigger 5 of the spray gun 1 should be actuated while the spray gun1 is still in the inverted position.

After use, when the spray gun 1 is to be cleaned, the spray gun 1 can bere-inverted from its operating position shown in FIG. 1, the airlinedisconnected and the trigger 5 actuated briefly to allow paint withinthe spray gun 1 to drain back into the liner 9 in the pot 6. The pot 6is then removed from the spray gun 1 by detaching the spout 15 from theadapter 18 which remains on the spray gun 1.

The collar 11 is removed from the container 8, and the lid 10 is thenpulled out, bringing with it the collapsed liner 9 as shown in FIG. 5.The lid 10 (including the filter 17) and liner 9 are discarded, leavingthe container 8 and collar 11 clean and ready for re-use with a freshliner 9 and lid 10. Only the spray gun 1 itself needs to be cleaned,resulting in a substantial reduction in the amount of solvent used.

The risk of unused paint spilling from the pot 6 is also substantiallyreduced because the liner 9 is removed and discarded in a somewhatcollapsed condition with the lid 10 in place. Moreover, because theliner 9 is discarded in a collapsed condition, the amount of spacerequired for collection of used liners 9 is minimised.

As will be apparent from the foregoing description, the arrangement ofthe disposable liner 9 and lid 10 forming a reservoir to contain thepaint or other liquid to be sprayed considerably reduces the amount ofcleaning required when changing the liquid to be sprayed or when puttingthe spray gun 1 away at the end of the working day.

It can happen, however, that the area to be painted requires a largervolume of paint than the reservoir can hold. In these circumstances, theuser has to remove the pot 6 from the spray gun 1, release the collar 11and remove the lid 10 to allow the reservoir to be topped up. The lid 10then has to be relocated on the open end of the liner 9, the collar 11refitted and the pot 6 reattached to the spray gun 1 to enable the userto continue spraying. This is time consuming and there is a risk ofpaint being spilt and/or contaminated when the lid 10 is removed.

Some users may try to re-fill the reservoir through the spout 15, butthis is even slower with increased risk of spillage due to the smallsize of the spout 15 and the presence of the filter 17. Also, any solidparticles trapped by the filter 17 when re-filling through the spout 15are on the wrong side of the filter 17 when the reservoir is re-attachedto the spray gun 1. As a result, these particles are entrained in theliquid delivered to the spray gun and this may lead to blockage withinthe spray gun or re-working of any surface finish contaminated with theparticles.

In order to avoid these problems, some users fill two or more reservoirswith the same liquid that can be fitted to the spray gun in turn whenspraying large areas. This enables the user to change over thereservoirs and continue spraying with the same liquid. However, fillingand assembling several reservoirs is time consuming and adds tooperating costs. Thus, each reservoir has a disposable liner and lidwhich is discarded after spraying and use of several reservoirs for thesame liquid is wasteful of such disposable items and requires the userto have available a sufficient number of pots and collars for assemblyof the reservoirs.

Referring now to FIGS. 8 to 12 of the drawings, there is shown a firstembodiment of the present invention which enables the user to add paintto the reservoir without disassembly of the reservoir. For convenience,like reference numerals in the series 100 are used throughout toindicate parts corresponding to FIGS. 1 to 7 and the construction andoperation of similar parts will be understood from the description aboveand will not be further described in detail.

As shown the paint pot 106 includes an outer container 108, a disposableliner 109, a disposable lid 110 and a collar 111 that are assembled insimilar manner to the previous embodiment. In accordance with thepresent invention, the lid 110 has a central opening 130 bounded by anexternal tubular spigot 131 and a separate cap member 132 is providedfor connecting the pot 106 to a spray gun (not shown). By locating theopening 130 centrally, the size of the opening 130 can be maximised fora given available space.

The cap member 132 comprises a base 133 having a socket 134 with aninternal screw thread 135 engageable with a complementary external screwthread 136 on the spigot 131 to secure releasably the cap member 132 tothe lid 110 in a fluid-tight manner. It will be understood thatadditional sealing means may be provided to prevent leakage if required.For example the outer end of the spigot 131 may engage an 0-ring (notshown) located within the cap member 132.

The cap member 132 also has a spout 115 extending from the base 133 andproviding a fluid outlet for connection to a fluid inlet on the spraygun 101 via an inlet adaptor (not shown) releasably secured to the spraygun. In this embodiment, the cap member 132 is releasably secured to theinlet adaptor by engagement of bayonet formations 116 on the spout 115with complementary bayonet formations (not shown) on the inlet adaptor.

The bayonet formations require less than one complete turn of the capmember 132 relative to the inlet adaptor to secure/release the reservoirwhereas the screw threads on the cap member 132 and spigot 131 requiremore than one complete turn of the cap member 132 relative to thereservoir to connect/disconnect the reservoir. In this way, accidentalor unintentional release of the reservoir from the cap member 132 isprevented when attaching/detaching the cap member 132 to/from the spraygun.

As can be seen from FIGS. 10 and 12, the internal diameter of the spout115 is considerably smaller than the diameter of the central opening 130in the lid 110 of the reservoir. For example, in this embodiment, thespout 115 has an internal diameter of 10-15 mm (approximately ½″) andthe central opening 130 has an internal diameter of 53 mm (approximately2″). The spout 115 is coaxial with the central opening 130 so that, whenconnected to the spray gun, the reservoir is aligned with the centrallongitudinal axis of the spray gun. As a result, the weight of thereservoir and the liquid therein is evenly distributed so that balance,handling of the spray gun is not adversely affected.

The opening 130 is oversize relative to the required flow when thereservoir is connected to the spray gun and permits fast-filling of thereservoir with liquid added through the opening 130 when the pot 106 isdisconnected from the cap member 132. As a result, if it is desired totop-up the reservoir in use, the pot 106 can be detached from the capmember 132 by unscrewing the connection between the spigot 131 and thecap member 132 to provide access to the opening 130. Liquid can then beadded to the reservoir through the opening 130 and the pot 106re-connected to the cap member 132 on the spray gun 101.

In this way, fast filling of the reservoir is possible by pouring liquidfreely into the reservoir through the oversize central opening 130. Inthis way, addition of liquid to the reservoir can be carried outrelatively easily without dis-assembly of the pot 106 and with reducedrisk of spillage or contamination of the liquid. As will be appreciated,the central opening 130 may be used to add liquid to the reservoireither when topping up the reservoir in use or when first filling thereservoir prior to commencing spraying.

The opening 130 may also allow insertion of a tool to stir the contentsof the reservoir allowing mixing to be carried out in the reservoirafter the pot 106 has been assembled to secure the lid 110 to the liner109. In this way, the risk of spillage is further reduced.

A filter (not shown) may be provided in the cap member 132 to remove anycontaminants such as solid particles in the liquid. For example, afilter may be positioned in the spout 115 or in the socket 134 so as toextend across the inner end of the spout 115 when the lid 110 isconnected to the cap member 132. In this way, if the filter becomesblocked in use, the cap member 132 may be replaced.

Alternatively, a removable filter (not shown) may be located in thecentral opening 130 when adding liquid to the reservoir. The filter maybe of any type and preferably has a large surface area so that theaddition of liquid to the reservoir is not significantly reduced. Inthis way, provision of a filter in the cap member 132 may be dispensedwith thereby reducing the risk of interruption or reduction in the flowof liquid to the spray gun due to blockage of the filter in use.

Referring now to FIG. 13, there is shown a second embodiment of thepresent invention in which like reference numerals in the series 200 areused to indicate parts corresponding to the previous embodiments and theconstruction and operation of similar parts will be readily understoodfrom the description already given and will not be further described indetail.

In this second embodiment, the liner 209 and lid 210 are permanentlyjoined together. For example, the liner 209 and lid 210 may be formedintegrally in one piece by blow moulding. Alternatively, the liner 209and lid 210 may be formed separately by moulding and connected togetherby welding, adhesive or other suitable means of forming a permanent jointherebetween.

The reservoir formed by permanently joining the liner 209 and lid 210may be used without the outer container and collar of the previousembodiments. Alternatively, some form of external support for the liner209 may be provided to protect the liner 209 and to improve stabilitywhen adding liquid to the reservoir and in use when the reservoir isconnected to a spray gun (not shown). The support (not shown) maycomprise an outer container and collar as described previously.Alternatively, the lid 210 may be formed with an external flange (notshown) or similar formation onto which a support sleeve or cage may bereleasably secured to surround the liner 209.

The reservoir may be supplied empty for the user to fill through thecentral opening 230 in the lid 210 prior to connecting the reservoir tothe spray gun. Alternatively, the reservoir may be supplied pre-filledwith liquid and the central opening 230 in the lid 210 sealed by aremovable closure (not shown) such as a screw cap 238 or a rupturablemembrane such as a foil strip. Where provided, the rupturable membranemay be broken when the cap member 232 is attached to the reservoir.

Pre-filling may be advantageous for liquids that can be stored withoutdegrading and/or which do not require accurate colour matching such asprimer paints or clearcoat lacquers. It may also be possible to storetemporarily any unused liquid on removal of the reservoir from the spraygun by re-sealing the opening 230 in the lid 210 with the screw cap 238(where provided) or any other suitable closure. This may allow theliquid to be used later by re-attaching the reservoir to the spray gunand is of potential benefit for liquids that do not cure and hardenwithin a relatively short period of time after first use. The reservoirmay be collapsed to remove any air prior to attaching the screw cap 238.In this way, the life of the stored liquid may be extended.

Referring now to FIGS. 14 and 15, there is shown an alternative capmember and inlet adaptor for use with the reservoir of the presentinvention. For convenience, like reference numerals in the series 300are used to indicate parts corresponding to the previous embodiments andthe construction and operation of similar parts will be readilyunderstood from the description already given and will not be furtherdescribed in detail.

In this third embodiment, the cap member 332 for connecting thereservoir (not shown) to the spray gun (not shown) is provided withreleasable connector means separate from the spout 315. The connectormeans comprises a pair of hook members 339, 340 arranged on oppositesides and spaced from the spout 315. Each hook member 339, 340 issimilar and has an enlarged head 341, 342 respectively with a chamferface 341 a, 342 a terminating at an undercut rib 341 b, 342 b.

The inlet adaptor 318 on the spray gun has an external flange 343 at theouter end for co-operating with the hook members 338, 339 to securereleasably the reservoir to the spray gun with the spout 315 received inthe socket 319. In this embodiment, the spout 315 has external annularribs 344 that provide a fluid-tight seal within the socket 319. It willbe understood, however, that any suitable sealing means may be providedsuch as one or more O-rings in the socket 319 and/or on the spout 315.

As best shown in FIG. 15, the flange 343 comprises four arcuate recesses345, 346, 347, 348 uniformly spaced in a circumferential directionaround the outer periphery such that the recesses 345, 347 are oppositeeach other and the recesses 346, 348 are opposite each other.

Each recess 345, 346, 347, 348 leads in a clockwise direction (as viewedin FIG. 15) via a cam lobe 345 a, 346 a, 347 a, 348 a at the end of therecess 345, 346, 347, 348 to a flat 349, 350, 351, 352 that terminatesin an abutment 349 a, 350 a, 351 a, 352 a.

In use, to secure the cap member 332 to the inlet adaptor 318, the hookmembers 338, 339 are aligned with a pair of opposed recesses 345, 347 or346, 348 in the flange 343. The spout 315 is then pushed into the socket319 so that the enlarged heads 341, 342 at the distal ends of the hookmembers 338, 339 pass through the aligned recesses 345, 347 or 346, 348.

The cap member 332 is then rotated relative to the inlet adaptor 318 tocause the hook members 338, 339 to ride over the cam lobes 345 a, 347 aor 346 a, 348 a and locate locking ribs 341 b, 342 b of the heads 341,342 behind the flats 349, 351 or 350, 352. In this way, the cap member332 is secured to the inlet adaptor 318 and axial separation of the capmember 332 from the inlet adaptor 318 is resisted. The cap member 332can be detached from the inlet adaptor 318 by reversing the aboveoperation.

As shown in FIG. 14, the cap member 332 may be secured to a reservoir byengagement of the internal screw thread 335 of the socket in the base ofthe cap member 332 with the external screw thread 335 on the spigot 331surrounding the central opening 330 in the lid 310 of the reservoir. Thelid 310 and liner 309 may be releasably secured together as shown inFIGS. 8 to 12 or permanently connected as shown in FIG. 13.

Referring now to FIGS. 16 and 17, two alternative arrangements forreleasably securing the cap member to the reservoir are shown forconvenience, like reference numerals in the series 400 and 500 are usedto indicate parts corresponding to the previous embodiments.

As shown in FIG. 16, the opening 430 in the lid 410 is provided with aninternal screw thread 450 and the base of the cap member 432 has aspigot 451 with an external screw thread 452 that is engageable with thescrew thread 450 to secure releasably the cap member 432 to thereservoir.

In FIG. 17, the lid 510 and cap member 532 are provided withcomplementary formations engageable with a snap action to securereleasably the cap member 532 to the reservoir around the opening 530.In this embodiment, the complementary formations comprise an externalrib 560 on spigot 531 and an internal groove 561 in socket 534. It willbe understood, however that any suitable formations may be employed.

Other arrangements for releasably securing the cap member to thereservoir will be apparent to those skilled in the art.

As will now be appreciated, the present invention provides liquid supplyapparatus for use with a spray gun including a reservoir having anoversize, fast-fill central opening and a separate cap memberconnectable to the reservoir with a spout providing a fluid outlet forconnection to the spray gun. In this way, the reservoir can be detachedfrom the cap member allowing liquid to be added to the reservoir throughthe central opening in a simple manner with reduced risk of spillage.Furthermore, by locating the opening centrally of the available space,the size of the opening can be maximised. Moreover, by arranging theoutlet of the cap member coaxial with the opening, the reservoir isaligned with the central longitudinal axis of the spray gun so thatbalance, handling of the spray gun is not adversely affected.

It will also be appreciated that the exemplary embodiments describedherein are intended to illustrate the diverse range and application ofthe invention and that features of the embodiments may be employedseparately or in combination with any other features of the same ordifferent embodiments.

Moreover, while the exemplary embodiments described and illustrated arebelieved to represent the best means currently known to the applicant,it will be understood that the invention is not limited thereto and thatvarious modifications and improvements can be made within the scope ofthe claims hereinafter.

1. A liquid supply assembly for use with spraying apparatus such as aspray gun comprising a reservoir for a liquid to be sprayed, thereservoir having a first end, a second end spaced from the first end, anend wall at the first end, a side wall extending from the end wall tothe second end, the end wall having a spout providing a fluid outletcommunicating with the reservoir, wherein the spout is connectable to aspray gun for connecting the reservoir to a fluid inlet of the spray guncharacterised in that the spout is provided by a cap member releasblysecured to the reservoir around an opening in the end wall, wherein amarginal edge of the opening is spaced inwardly from the side wall atthe first end, and the reservoir can be detached from the cap member foradding fluid to the reservoir through the opening in the end wall. 2.The assembly of claim 1 wherein the opening in the end wall is oversizerelative to the spout.
 3. The assembly of claim 1 wherein the reservoiris collapsible as liquid is withdrawn.
 4. The assembly of claim 3wherein the side wall is flexible in comparison to the end wall so as tobe capable of deforming to collapse the reservoir in an axial directionfrom the second end towards the first end.
 5. The assembly of claim 4wherein the reservoir is provided with a comparatively-rigid base at thesecond end such that the reservoir can be inverted and stood on the basefor adding liquid through the opening in the end wall.
 6. The assemblyof claim 5 wherein the reservoir is formed in one piece.
 7. The assemblyof claim 5 wherein the base and side wall are formed in one piece withthe end wall being formed as a separate piece that is secured to theside wall.
 8. The assembly of claim 7 wherein the base and side wallform an open topped container and the end wall forms a lid for thecontainer.
 9. The assembly of claim 8 wherein the lid is permanentlysecured to the container.
 10. The assembly of claim 9 wherein the lid iswelded or adhesively bonded to the container.
 11. The assembly of claim8 wherein the lid is releasably secured to the container.
 12. Theassembly of claim 11 wherein the lid is clamped to the container. 13.The assembly of claim 1 wherein the cap member is a screw-fit on thereservoir.
 14. The assembly of of claim 1 wherein the cap member is asnap-fit on the reservoir.
 15. The assembly of claim 13 wherein the capmember comprises a base defining a socket with an internal screw threadengageable with an externally threaded spigot bounding the opening inthe reservoir.
 16. The assembly of claim 13 wherein the opening in thereservoir has an internal screw thread and the cap member has a baseprovided with an externally threaded portion engageable with theinternal screw thread.
 17. The assembly of claim 2 wherein the spout hasa diameter less than half the diameter of opening.
 18. The assembly ofclaim 17 wherein the spout has a diameter less than a third the diameterof the opening.
 19. The assembly of claim 18 wherein the spout has adiameter less than a quarter the diameter of the opening.
 20. Theassembly of claim 19 wherein the opening has a diameter of 50-60 mm andthe spout has a diameter of 10-15 mm.
 21. The assembly of claim 1wherein the reservoir has a central longitudinal axis and the opening islocated centrally on the longitudinal axis.
 22. The assembly of claim 21wherein the spout is coaxial with the opening.
 23. The assembly of claim1 wherein the cap member is releasably connectable to the sprayingapparatus.
 24. The assembly of claim 23 wherein the cap member andspraying apparatus are provided with co-operating bayonet typeformations.
 25. The assembly of claim 24 wherein the spraying apparatusis provided with a socket to receive the spout and the bayonet typeformations are engageable to retain the spout in the socket.
 26. Theassembly of claim 25 wherein the bayonet type formations are engageablewithin the socket.
 27. The assembly of claim 26 wherein the spout isprovided with opposed bayonet lugs at the free end that are received inbayonet grooves in the socket.
 28. The assembly of claim 25 wherein thebayonet type formations are engageable externally of the socket.
 29. Theassembly of claim 28 wherein the socket has an external flangeco-operable with a pair of hook members extending from the cap member onopposite sides of the spout.
 30. The assembly of claim 1 wherein the capmember includes a filter for removing any unwanted solid particlescontained in the liquid withdrawn from the reservoir.
 31. The assemblyof claim 30 wherein the filter is located in the spout.
 32. The assemblyof claim 30 wherein the filter is located in the cap member to extendacross the inner end of the spout.
 33. The assembly of claim 1 whereinthe opening is sealed.
 34. The assembly of claim 33 wherein the openingis sealed using a removable closure or a rupturable membrane.
 35. Theassembly of claim 34 wherein the cap member is adapted to rupture themembrane.
 36. The assembly of claim 33 wherein the cap member is adaptedto seal the opening until it is desired to use the liquid.
 37. Theassembly of claim 36 wherein the cap member is provided with a removableelement to close the spout.
 38. The assembly of claim 36 wherein arupturable membrane is provided across the outer end of the spout. 39.The assembly of claim 38 wherein the spraying apparatus is adapted torupture the membrane.
 40. The assembly of claim 1 wherein the cap memberhas a base and a spout, the cap member being releasably secured to thereservoir by engagement of complementary screw threads on the base andon the end wall around the opening, and the spout extends from the baseaway from the reservoir, the spout providing a fluid outlet of reducedcross-section relative to the opening.
 41. The assembly of claim 40wherein the reservoir is collapsible as liquid is withdrawn in use. 42.The assembly of claim 40 wherein the reservoir has a centrallongitudinal axis and the opening and spout are arranged coaxially withrespect to the longitudinal axis.
 43. The assembly of claim 40 whereinthe screw threads on the reservoir and cap member require more than onecomplete turn to secure the reservoir, and the cap member is releasablyconnectable to the spray gun by means requiring less than one completeturn.
 44. The assembly of claim 1 wherein the opening is oversizerelative to the flow requirements when the reservoir is connected to thespray gun in use, and the fluid outlet provided by the spout is ofreduced cross-section relative to the opening, wherein the openingpermits fast-filling of the reservoir when the cap member is detachedfrom the reservoir for adding fluid to the reservoir through theopening.
 45. The assembly of claim 44 wherein the reservoir iscollapsible in use as liquid is withdrawn.
 46. The assembly of claim 44wherein the reservoir has a base at the second end and is free-standingon the base.
 47. The assembly of claim 46 wherein the base, side walland end wall are permanently joined together.